Water leaking out of a water pipe is bad enough. Rainwater leaking into a sewer collections system is a headache of another sort because it strains wastewater treatment facilities. Then there’s the matter of wastewater leaking out into neighboring soils, introducing pollutants into groundwater. Indianola, Iowa, has experienced all of the above but is well on its way to restoring the integrity of its sewer lines.

The Warren County seat in south-central Iowa had an awakening...